13 March 2018 In-cell overlay metrology by using optical metrology tool
Author Affiliations +
Abstract
Overlay is one of the most critical process control steps of semiconductor manufacturing technology. A typical advanced scheme includes an overlay feedback loop based on after litho optical imaging overlay metrology on scribeline targets. The after litho control loop typically involves high frequency sampling: every lot or nearly every lot. An after etch overlay metrology step is often included, at a lower sampling frequency, in order to characterize and compensate for bias. The after etch metrology step often involves CD-SEM metrology, in this case in-cell and ondevice. This work explores an alternative approach using spectroscopic ellipsometry (SE) metrology and a machine learning analysis technique. Advanced 1x nm DRAM wafers were prepared, including both nominal (POR) wafers with mean overlay offsets, as well as DOE wafers with intentional across wafer overlay modulation. After litho metrology was measured using optical imaging metrology, as well as after etch metrology using both SE and CD-SEM for comparison. We investigate 2 types of machine learning techniques with SE data: model-less and model-based, showing excellent performance for after etch in-cell on-device overlay metrology.
Conference Presentation
© (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Honggoo Lee , Honggoo Lee , Sangjun Han, Sangjun Han, Minhyung Hong, Minhyung Hong, Seungyoung Kim, Seungyoung Kim, Jieun Lee, Jieun Lee, DongYoung Lee, DongYoung Lee, Eungryong Oh, Eungryong Oh, Ahlin Choi, Ahlin Choi, Hyowon Park, Hyowon Park, Waley Liang, Waley Liang, DongSub Choi, DongSub Choi, Nakyoon Kim, Nakyoon Kim, Jeongpyo Lee, Jeongpyo Lee, Stilian Pandev, Stilian Pandev, Sanghuck Jeon, Sanghuck Jeon, John C. Robinson , John C. Robinson , } "In-cell overlay metrology by using optical metrology tool", Proc. SPIE 10585, Metrology, Inspection, and Process Control for Microlithography XXXII, 105851D (13 March 2018); doi: 10.1117/12.2300946; https://doi.org/10.1117/12.2300946
PROCEEDINGS
9 PAGES + PRESENTATION

SHARE
Back to Top